BART (in full, San Francisco Bay Area Rapid Transit District) is a rapid transit electric train service that serves parts of the San Francisco Bay Area, including the cities of San Francisco and Oakland. The trains are computer-controlled and arrive on-time with regular accuracy. Drivers are present in case of unforseen difficulties.

The BART system was first proposed in 1946 by Bay Area business leaders concerned with increasing post-war migration and congestion in the region. An Army-Navy task force concluded that another trans-bay crossing would soon be needed to relieve congestion on the San Francisco-Oakland Bay Bridge. The idea of an underwater electric rail tube was deemed the best solution in conjunction with a multiple-county rapid transit rail system.

Enormous construction tasks were at hand, including underground rail sections below downtown Oakland and Market Street in San Francisco, and a tunnel through the Berkeley Hills, as well as the 3.8-mile transbay tube itself, which was lowered to the bottom of the bay by a small armada of construction vessels. The tube, constructed in 57 sections, was completed in August 1969 at a cost of $180 million.

A $1.4832 billion extension of BART southward beyond Colma is nearing completion. Ground was broken in November 1997, and the first trains are set to run on June 22, 2003. The extension will add four new stations in South San Francisco, San Bruno, Millbrae, and, via a spur, San Francisco International Airport. The project encompasses 8.7 miles of new rail track, of which 6.1 miles is subway, 1.2 miles is aerial, and 1.4 miles is at-grade.
[1] (http://www.bart.gov/news/features/news_8466.asp) [2] (http://www.sfgate.com/cgi-bin/article.cgi?file=/chronicle/archive/2003/04/18/MN89853.DTL)

An extension of BART southward past Fremont towards San Jose is also proposed, but studies remain to be completed and funding to be acquired.